Eleaf iStick TC100W Power Limit, Battery Config. and Impressions

So after researching a few mod options I narrowed it down to the Eleaf iStick TC100W as my potential next mod purchase, watching a couple video reviews the design is so cool for my taste and quality of the case and finish is quite nice, it is also something new in terms of how it could run on one or two batteries, have a hidden firing button and a dedicated menu key.

Few things about it are confusing me a bit so I could use your thoughts and comments

1- this device runs on two PARALLEL 18650 high drain batteries (25A+ are recommended by the manufacturer) what implications does the parallel batteries setup has on its operations, from what I understand parallel configuration doubles the current output , does this mean that this mod could potentially output 50A , also why do you think is the reason for its 100W upper limit?

2- in the review the guy says he has been vaping on it for a full day and the battery still has like 75% charge left in it? Again what implications does the parallel setup has on battery life?

3- this has a bypass mode, again what are the differences with bypass in parallel vs. Serial configuration?

4- some people mentioned that the isticks catch fire or something like that, is this a current issue or a problem of the past?

5- lastly does anyone have a link to pre-order this mod for a good price?

From what I understand, it's pretty newly announced, so there probably won't be much first hand info on it yet.
However, based on my knowledge of general electrical and vaping info...

1. Yes, in parallel, you have the amp capacity of both batteries combined, with the same voltage as one alone. This won't mean much using a regulated mod. The chip will take the batteries' output and convert it to what you choose to apply to the atomizer, within it's parameters, employing what I assume to be some kind of witchcraft (I don't know a lot about electronics. Someone more knowledgeable can fill in this part of they want to).

2. Battery life depends entirely on use; how much are you using it at what wattage? "Vaping on it for a full day" means something different for each of us. Really it depends on total run time (combined total time the fire button is down) and the power level it's set at. Steam-engine.org or the "vape tool" app have good calculators for that.
3. Bypass mode, assuming it uses the same definition as other mods, will be like using a mechanical mod. It will apply the voltage of the batteries. So as they drain, the voltage will go down. Two cells in parallel will have 4.2 volts at full charge, down to whatever eleaf decides is the cutoff.
This is still generally subject to the other limitations of the device. Nothing over 100w obviously, but it also still won't fire a build lower than the device's minimum resistance, or one that exceeds its maximum ampere output. That's a harder specification to find sometimes, but many will not be able to fire their minimum resistance atomizer at their full wattage.

4. There have been reports of isticks, especially the 50w, but I think also the 100w(non tc), having battery failures during USB charging. I haven't followed closely enough to know whether fires were involved. A good external charger should negate this issue. (If I'm mistaken, may I be corrected by the more knowledgeable)

5. Sorry, I've already ordered a Kbox 120w to scratch the itch that this mod would, and don't feel like searching Google for you.

Best of luck finding a new mod. Just remember that joyetech, that seem to have burned you so bad with the cuboid, are part of the same company as eleaf, the producers of the isticks.

1- The thing that i don't fully understand is that every other two battery mod would do at least 133W (DNA200) and more commonly 150W with some reaching a theoretical 200W, my experience with the Cuboid which has the batteries connected in series would have the voltage of the two batteries combined and then the DC-DC regulation chip would decrease/increase that voltage for up to 9V and 25A reaching a total power output of 200W in the best case scenario, what i don't understand is how would a DC-DC chip do the same when only a max voltage of 4.2V when fully charged is available to it but the full amperage output of two batteries, this DC to DC conversion is pretty confusing to me at this point i think i need to read about it much more to understand what is going on under the hood of regulated serial vs. regulated parallel setups.

2- Steam-Engine calculations assume that only one battery is in use, without proper theory in place i can not really estimate what happens with two batteries connected in parallel, this device can run on only one battery for up to 75W, adding another battery increase that by up to another 25W only for a total of 100W, from the looks of it it seems that it is not hitting the batteries as hard as other devices, for example my Cuboid with 2 VTC4s would not last me a whole day with average to heavy vaping on 45-50W, it seems that the istick is able to get more battery life with its parallel configuration for some reason which i do not yet understand, chip efficiency is increased with this battery setup maybe?

3- Bypass is easy to understand with one battery in place, but i do not understand how to calculate what happens in Bypass mode with two batteries connected in parallel, i understand that the max voltage i would get is 4.2V when fully charged, but what are the implications on Amps and wattage with this setup in bypass?

4- Interesting i will dig this up some more.

5- No problems at all, this question is for those people who already have link with coupon codes and such for stores they trust, so don't worry about it, i did not intend for people to do a Google search for me

Best of luck finding a new mod. Just remember that joyetech, that seem to have burned you so bad with the cuboid, are part of the same company as eleaf, the producers of the isticks.

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unfortunately Joyetech has a stake someway or another in the companies/chips of all the mods i am considering, Cuboid, eVIC Mini are by them, the Wismec Classic and RX200 is made by them, they also seem to be eleaf's parent company, they have the best non-DNA200 chip in the market right now, they are the only non-DNA200 chip maker that have manual TCR settings, native SS316 support and firmware upgrade ability all of which are things i need so i have no other way but to buy something that is at least partially made by them.

This brings me to a different way of thinking, in the past couple of days i saw pictures posted by other Cuboid owners that looks perfect, it is nothing like the device i received, very neatly assembled cases, perfect screen alignment and condition etc.. most of these pictures came from people here in VU which i am not sure if they purchased their device in the US or directly from China.

After reflecting a bit on this information i am starting to believe that Joyetech's quality problems happen at the assembly line and not the manufacturing process itself, quality issues could be region/market specific or batch related, i am not sure how is this exactly happening, but either in some times they are under higher pressure to produce more which decreases the assembly line precision or that they produce different quality of the same product for different markets/regions or maybe there was a bad batch in which i got one of its products .. also Joyetech's factory could be different from Wismec and eleaf factories even if they are owned by the same company which could result in different assembly/product quality.

In the video i watched, the istick the guy was showing was very neat and clean, also in other pics the Cuboid looks neat, but after my experience with the Cuboid sample i received i just don't feel like trying another one anyways, i just developed a hate relationship with it, so i am probably better off, at least psychologically of trying another mod even if it is by the same company than i am by giving the Cuboid another try.

Most regulated mods run batteries in series, giving you higher voltage, allowing more power to be applied to the coil. Since this one runs in parallel, it runs off the same principles of single batteries. A general rule of thumb is a single 18650 can only truly achieve 75W, anything more is PWM (Pulse Width Modulation - Pulsing the battery on and off very fast to attain a higher Amp limit). That's why batteries are rated for CDR and Pulse.
Essentially: Series = stacked (double the power/volts) / Parallel = side by side (double the mah and amp)
So an easier way to think about it is parallel is like melding 2 batteries to create one fat battery. It'll give you the same power output but longer battery life by sharing the load between 2 cells.
[Visualize 2 vehicles. One has two 100HP motors, the other has one 200HP motor. The car with 1 motor will go faster, but run out of gas sooner. The other will go slower, but run for twice as long.]
So in series, 2 18650 batteries could give you 150W of true power, the other 50W coming from pulsing the batteries to attain a higher Amp draw. This mod has 2 batts in parallel, so it has 75W of true power in single cell, and will get 100W with the dual cells. A single battery mod could potentially do 100W, but it would be more dangerous. With the parallel setup, it gives you double the amps, so it doesn't stress the batteries as hard when pulsing them)
The bypass mode will act like a mech mod, but with be limited to what the mod can fire in power mode (Ex. so if the mod can only fire down to 0.2ohm power mode, even in bypass mode it won't fire anything below 0.2ohm). The nice thing about this feature is if you're an actual mech user, you will now be able to see what is actually being drawn from the battery as you use it, instead of guessing like with a mech (like using a mech mod with real-time usage stats). With 2 batteries, it'll do the same thing, just the levels will take longer to diminish as you use it.
As for the fires, those were mainly from the first batch of the iStick 50W, there was a QC issue on the first run, which they later rectified.
Hopefully that makes sense, if not come back and ask more questions

Very good observations DED420. Our question over here is that if it runs in a series, would it counteract the problems that the RX200 has of unevenly distributing the mAh of the batteries? We've run into some issues of the RX200 having one battery being fuller than the other two. With that said, the TC100W only uses two batteries which may be better for this situation, however it may be using a similar chipset to the Joyetech RX200. (Eleaf and Joyetech are the same company).

Very good observations DED420. Our question over here is that if it runs in a series, would it counteract the problems that the RX200 has of unevenly distributing the mAh of the batteries? We've run into some issues of the RX200 having one battery being fuller than the other two. With that said, the TC100W only uses two batteries which may be better for this situation, however it may be using a similar chipset to the Joyetech RX200. (Eleaf and Joyetech are the same company).

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Yeah, it shouldn't be an issue with this mod. Most series mods don't have that problem, the Reuleaux RX200 is a different beast (ParaSeries mod). In most Series, when you pull the batts, one will be very slightly more than the other, because of how power flow works, one battery is supplying the power and the other is charging the first, essentially. That's why it's essential to rotate them, to work/stress them both evenly. With the RX200, it's like having 1 battery do the work, and the other 2 are charging the first. This makes rotating them more difficult.

Lets see if I can make an understandable example. You have 3 new batts. 1 as "power" (serial), 2 as "charge" (parallels). Batt (A) will be power, batt (B) & (C) are charge. VapeVapeVape. Now batt (A) is stressed, (B) & (C) not. Rotate and batt B is now power. So now one stressed batt (A) and one unstressed batt (C) are charging batt (B), in parallel, but since one is stressed already, the 2 charge batts (A) & (C) are working/draining unevenly. Rotate and batt (C) is charge, and (A) & (B) are charge. Now all 3 batts are working at different levels. As this circle continues, the charge rates are going to steadily get worse.

I think that made sense Or at least that's how my logic seems to be dictating it to me. With an uneven number of batts, there's always going to be power level fluctuations, I'm just unsure if the differences will eventually add up and make the batts unusable together (too large a difference between levels to be safe).

Hopefully someone with more experience with triple batt mods can chime in and confirm if my reasoning is correct or not. Hope that helps

@DED420 WOOW you are so knowledgeable about this, one of the most useful and informative posts i have read so far, of the type that i will keep referring back to and re-reading every time i feel confused about this topic, thank you so much for making the effort to communicate the idea as clearly as you did.

I am still wondering about something tough, in all your logic and explanations you treat parallel config as one big battery with double the mAh capacity with no regard to the current doubling effect, lets take the VTC4 battery as an example which is the one i am currently using, it is a 2100 mAh battery with an up to 30A CDR, now my understanding is that if you connect these in parallel you should get one big battery with 4200 mAh capacity, 60A CDR and 4.2V, now why would the DC-DC chip only be able to output a continuous 75W only when it has 60A at its disposal to use and which could probably be converted into more power reaching the same level of mods with serial configuration? Why does it even need to pulse the batteries when they could easily handle 50-60A CDR?

Off the top of my head, one reason could be that they can't assume you're gonna use 30A CDRs batteries, they have to play it safe and assume you only have 20A CDRs, maybe? (plus some other contributing factors I can't seem to remember/explain)

This one may take me a while to formulate a proper response. Give me some time to get back to you on this, hopefully I can make a coherent explanation lol.

In the meantime, maybe someone else might be able to chime in and help us out, I feel as though I have the exact answer you need in my head, but just can't seem to get it out

Off the top of my head, one reason could be that they can't assume you're gonna use 30A CDRs batteries, they have to play it safe and assume you only have 20A CDRs, maybe? (plus some other contributing factors I can't seem to remember/explain)

This one may take me a while to formulate a proper response. Give me some time to get back to you on this, hopefully I can make a coherent explanation lol.

In the meantime, maybe someone else might be able to chime in and help us out, I feel as though I have the exact answer you need in my head, but just can't seem to get it out

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Take all the time you need, i know the feeling and are sure that you will figure it out at the end after some thinking and reflection

One thing to add though to consider while you are thinking about this, in the case of iStick TC100W they are not assuming or predicting that you would use 20A CDRs but actually explicitly recommend/require 25A+ for use with the device. The following quote comes directly from the product specs in the official website here http://www.eleafworld.com/istick-tc100w-firmware-upgradable/

Ok, I think I confused us a little there because I mistakenly said 2 parallel cells would pulse to get 100W earlier (oopsy), so I edited it correctly for future reference.....when the mod is run in single cell, it'll only get 75W, and a single cell would need to pulse to achieve "100W" (this mod won't do that though). With 2 parallel cells, a mod could achieve a true 100W without any pulsing, even 150W without pulse, but would then pulse for the extra "50W+". So knowing that this mod can't fire below 0.05Ω and can only go to 100W, with 25A+ CDR this mod wouldn't need to pulse your batteries at all.

They could have made this mod to run at higher wattages, but they obviously chose not to for whatever reason (wouldn't have any idea why) though they'll likely release a firmware upgrade to 150W later, so that should be something to look forward too.

Hope I cleared up your confusion, that was my bad Feel free to ask anything that I may have missed, always glad to help

I'm just a old dumb ass. But let me put this battery issue in another way to look a how stuff works. It's funny how this example parallels. battery's.

I can take two identical pumps with design conditions the same, like 500gpm @ 100' of head. That is there design conditions with a 20hp motor with the design conditions spec'ed at non over loading. Meaning we will never over load the motors and let the smoke out. It will also be the most eff. choice as messured from the eye of the impeller to the outside edge of the impeller.

If I install and pipe this pair of pumps in serial,meaning one pump feeds the other. The 100' of head goes up to 185' of head/psi. The discharge pressure all most doubles. But the GPM ( gallons per minute ) Stays the same. Making the pumps put out more psi does not hurt the motors one bit. This config backs or install up the pump curve and unloads our gpm load. Lets call this our current load and output.

Now when I take the same two pumps. As if they were two battery's and hook them up parallel. My amps/psi stays the same as if there was only one of the pumps in the loop. But my GPM will almost double. So lets call this our MAH. GPM/MAH can hurt me if I let the pumps run out on the curve. They will pull more power and the motors could go into service factor or complete over load and fry the motors if there control are not set up right.

Battery curves work just like pump curves. None of this is rocket science. Except the is no sag. But the is low nphs. Nphs tells you how much water in psi you have to have feeding the pump after the water has made it loop. That is determined by pressure drop through the loop. So in a way is kind of like battery sag. If you don't have enough return psi your psi and gpm will drop. if you don't have it you can'r make it.

Ok, I think I confused us a little there because I mistakenly said 2 parallel cells would pulse to get 100W earlier (oopsy), so I edited it correctly for future reference.....when the mod is run in single cell, it'll only get 75W, and a single cell would need to pulse to achieve "100W" (this mod won't do that though). With 2 parallel cells, a mod could achieve a true 100W without any pulsing, even 150W without pulse, but would then pulse for the extra "50W+". So knowing that this mod can't fire below 0.05Ω and can only go to 100W, with 25A+ CDR this mod wouldn't need to pulse your batteries at all.

They could have made this mod to run at higher wattages, but they obviously chose not to for whatever reason (wouldn't have any idea why) though they'll likely release a firmware upgrade to 150W later, so that should be something to look forward too.

Hope I cleared up your confusion, that was my bad Feel free to ask anything that I may have missed, always glad to help

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After some little reading the only difference i found between series vs. parallel config. on a regulated mod is the DC-DC Chip controller efficiency difference, in series the batteries would be outputting a nominal combined 7.4V, so if you are vaping at say 5V the controller would have to buck/reduce the voltage coming directly of the battery, going with parallel at a nominal battery value of 3.7V the controller will have to boost the voltage to 5V to give you the same power.

They say it is more efficient for the controller to buck the voltage than it is for it to boost the voltage, resulting in relatively higher power output and slightly longer battery life.

BUT in single battery mods like the eVic VTC Mini the controller has no problem at all boosting the voltage to a max of 9V with only one 20-30A CDR battery, so with 40-60A CDR the controller in the iStick TC should have no issue whatsoever boosting the voltage to 9V or more.

Now this does not explain why can't the iStick achieve 150W comfortably while having access to two batteries, either it is a marketing plan to release it as 100W at first and then raise it to 150W with a future firmware upgrade or that they are using a very wide safety margin here, or they chose to go for longer battery life over more power by design. the older non-TC iStick 100W also uses two batteries in parallel and have the same 100W output limit with no opportunity for firmware upgrades.

The difference in efficiency with a buck vs. boost controller does not justify a 50W difference in output

I think it is time to send an email to eleaf asking for an explanation.

Off the top of my head, one reason could be that they can't assume you're gonna use 30A CDRs batteries, they have to play it safe and assume you only have 20A CDRs, maybe? (plus some other contributing factors I can't seem to remember/explain)

This one may take me a while to formulate a proper response. Give me some time to get back to you on this, hopefully I can make a coherent explanation lol.

In the meantime, maybe someone else might be able to chime in and help us out, I feel as though I have the exact answer you need in my head, but just can't seem to get it out

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I was thinking it could be because alot of battery brands are 'rewrapped with a higher amp rating stated than it has' like the efests, ive got two of the 2500mah '650s that show an amp rating of 35a. but thats the PULSE current it can handle, its truly only a 20a cdr rewrapped cell. it bothers me that efest doesnt list the rating as pulse or show both stats. that could get dangerous with a dumb kid, a couple eleafs and a series unreg. box mod if that kid decided "Imma build to 0.0004 ohms and blow SICK CLOUDS!"

For me RX200 is more realiable solution. I will explain why batteries in series > Batteries in parallel.
1. U got 2 x 2500mah 18650 in parallel = 5000Mah but 4.2V. When u vape at 100W, that means = 100w / 3.7V (nominal under load) = 27 Amp drain on battery, divide that by 2, u get 13.5 amps load on each battery. Leave the battery, it can withstand such power, but your chip is stuggling and getting hot converting that 4.2V to higher voltage output to gain that Wattage safely at atomizer, but it needs to pull 27 amps from battery. Imagine the strain put on input ports of invertor chip
2. U Got 2 x 2500mah 18650 in series = 2500mah 8.4V. At 100W load 100w / 7.4V = 13.5 amps. Chip needs no voltage invertion to achieve that wattage, it just gives 13.5 amps output and receives 13.5 amps on input ports. That makes it heat up less, less strain on invertor and less chance of failing because of temp and load.
3. U Got 3 x 2500mah 18650 in RX200 = 2500Mah 12.6V. at 100W load 100w / 11.1V = 9 amps total needed to achieve 100w. Chip does not even feel that load, neither battery, which prolongs battery life, almost generates no extreeme heat inside, and that 9amps load does not bring battery voltage below the minimum. Almost no chance of failing because of heat and strain on the chip invertor, tripple battery lifespan and good reliability

I think it's more helpful, Vapomizer, to think of amperage as being pulled or drawn out of a battery by the load rather than a battery pushing out the amperage. The load is going to draw whatever amps it draws. This is why it can be dangerous to use batteries that are not built to tolerate the loads low ohm builds draw...especially if you don't have electronics in between the load and the battery to mitigate an overload. Parallel batteries distribute or "split" the amperage being drawn by the load more or less evenly between them.